Modulation of gene expression by adenovirus transformation.

Abstract

Human adenoviruses (Ad) cause a productive infection in human cells, while in rodent cells in general they bring about only an abortive infection, which occasionally can lead to morphological transformation. In the transformed cells, viral DNA is integrated into the genome and at least the genes of the viral E1 region are expressed. This is consistent with the observation that the transforming activity of the virus is localized in region E1. Rodent cells, e.g., from rat, mouse, or hamster, can be transformed efficiently by Ad DNA, but human cells, including fibroblasts and epithelial cells, are extremely refractory to transformation. Only a few transformed cell lines have been isolated from human embryonic kidney cultures, in spite of considerable efforts (Graham et al. 1977; Byrd et al. 1982). In contrast, human embryonic retina cells can be transformed reproducibly with Ad DNA (Whittaker et al. 1984), although less efficiently than rodent embryo or kidney cultures. The E1 region consists of two transcriptional units, E1A and E1B. For complete morphological transformation both regions are needed, but the E1A region by itself can immortalize rodent cells (Houweling et al. 1980).